One septillionth (10−24 ).
One septillionth part of; the factor 10-24
Origin of yocto
- < octo-: because the number is 10-3 to the eighth power
From Webster's New World College Dictionary, 5th Edition
- Alteration of octo– (from its representing the eighth power of a thousandth)
From American Heritage Dictionary of the English Language, 5th Edition